How to Install a Kitchen Sink Water Filter

A kitchen sink water filter is a great way to ensure your drinking water is clean. A plumber can install a filter, or you can do it yourself. If you’re concerned about lead in water, choose a system that’s rated to remove lead. You can learn more about water filters and lead reduction by reading the the NSF’s guide. The NSF is a consumer group.

There are two main parts to the system: 1) an under-the-sink unit that contains two replaceable filters and 2) a compact faucet mounted on the sink or countertop.

The filter under the sink attaches to the water line. It feeds the water that passes through the two filters to the faucet.

Step 1

Turn off the water supply to the cold water line. Turn on the kitchen tap to check the water is off and relieve pressure in the line.

Step 2

Locate the cold water shutoff valve under the sink. Use a piece of emery cloth to clean the copper tubing. Use a close-quarters tube cutter to cut the tube just under the shutoff valve. Cut again about 1 inch below the first cut to remove that section of tubing. Slip the tee on the bottom part of the open section.

Step 3

Outside the sink, fit a ½-inch ball valve to two pieces of copper tubing and a female adapter. Solder this assembly together before you install it. For best results, start from the bottom of the assembly and work upwards.

Fit the finished assembly onto the tee you installed with a 90-degree elbow. At this point, solder both ends of the assembly in place.

Wrap Teflon tape to the reducer fitting and thread it into the female adapter while holding the adapter with pliers for support.

Step 4

Measure and mark the hole on the sink for the faucet. For a cast-iron sink, use the sprayer hole for the faucet. Drill a 1/2” hole with a step drill, slowly increasing the diameter with each step on the drill bit. If the drill skips around, use a small piece of masking tape on the hole to keep it in place. After the hole is finished, clean the area with a wet/dry vac.

Step 5

Place the washer, aluminum base and rubber gasket onto the threaded stem of the faucet. Slip the faucet into the hole and make sure it sits flat. From under the cabinet, reach up and place the mounting bracket, lock washer and hex nut onto the faucets stem. Tighten the hex nut carefully with a basin wrench.

Step 6

Remove the plastic cover from the filter and install the required battery. Next, cut a length of the plastic tubing that will reach from the cold water line reducer you installed to the filter where it will be mounted on the back wall of the cabinet. Push one side of the tubing into the fitting on the filter and attach the remaining end to the water line at the reducer.

Cut another length of tubing that will go from the opposite side of the filter up to the faucet.

Step 7

Select the spot on the back wall of the cabinet where the filter will sit. Mark the holes and drill pilot holes and insert anchors and screws. Slide the filter down on the screws through the keyholes and tighten the screws.

Step 8

Connect the remaining tubing to the faucet under the sink using a compression fitting. Turn your water supply back on and open the faucet, letting it run until you have an even flow of water.

This may test your DIY abilities. If you get yourself in a bind during any plumbing project, get in touch. Meticulous plumbers will quickly put things right.

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